Answer:
Step-by-step explanation:
The decay rate of strontium-90 is -.0244 as given.
For b., we have to use the formula to find out how much is left after 30 years. This will be important for part d.
[tex]A(t)=400e^{-.0244(30)}[/tex] which simplifies a bit to
A(t) = 400(.4809461353) so
A(t) = 192.4 g
For c., we have to find out how long it takes for the initial amount of 400 g to decay to 100:
[tex]100=400e^{-.0244t}[/tex]. Begin by dividing both sides by 400:
[tex].25=e^{-.0244t[/tex] and then take the natural log of both sides:
[tex]ln(.25)=lne^{-.0244t[/tex] . The natural log and the e cancel each other out since they are inverses of one another, leaving us with:
ln(.25) = -.0244t and divide by -.0244:
61.8 years = t
For d., we figured in b that after 30 years, 192.4 g of the element was left, so we can use that to solve for the half-life in a different formula:
[tex]A(t)=A_0(.5)^{\frac{t}{H}[/tex] and we are solving for H. Filling in:
[tex]192.4=400(.5)^{\frac{30}{H}[/tex] and begin by dividing both sides by 400:
[tex].481=(.5)^{\frac{30}{H}[/tex] and take the natural log of both sides, which allows us to pull the exponent out front. I'm going to include that step in with this one:
ln(.481) = [tex]\frac{30}{H}[/tex] ln(.5) and then divide both sides by ln(.5):
[tex]\frac{ln(.481)}{ln(.5)}=\frac{30}{H}[/tex] and cross multiply and isolate the H to get:
[tex]H=\frac{30ln(.5)}{ln(.481)}[/tex] and
H = 28.4 years
In the Data Analysis portion of the article the authors report that they completed a power analysis to determine the power of their study with the sample size utilized. They report a power of 90%. What does this mean
Answer:
Kindly check explanation
Step-by-step explanation:
The power of a test simply gives the probability of Rejecting the Null hypothesis, H0 in a statistical analysis given that the the alternative hypothesis, H1 for the study is true. Hence, the power of a test can be referred to as the probability of a true positive outcome in an experiment.
Using this definition, a power of 90% simply means that ; there is a 90% probability that the a Pvalue less Than the α - value of an experiment is obtained if there is truly a significant difference. Hence, a 90% chance of Rejecting the Null hypothesis if truly the alternative hypothesis is true.
I want to know how to solve this equation
Answer:
your answer will be Option D
Step-by-step explanation:
log 10
Ray’s weight increased by 11% in the last two years. If he gained 16.5 pounds, what was his weight two years ago?
Out of a total of 10 college textbooks estimate the standard deviation of their ages if the oldest textbook is known to be 7.9 years old and the newest textbook is 1.3 years old.
Answer:
Given that the maximum age of the textbook is 7.9 years and the minimum age of the textbook is 1.3 years.
Using the range rule, the standard deviation is estimated as,
S≈maximum−minimum/4
=7.9−1.3/4
=1.65
The required value of the approximate standard deviation is 1.65.
The standard deviation of the data is 1.65.
What is Standard Deviation?Standard deviation is the measure of the deviation of the data from the mean.
The total college textbooks is 10
The oldest book is 7.9 years old
The newest book is 1.3 years old
The standard deviation of range is equal to one fourth of the difference of maximum to minimum.
The standard deviation = ( 7.9 - 1.3 ) /4 = 1.65
To know more about Standard Deviation
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Write the point-slope form of an equation of the line through the points (-4, 7) and (5, 3).
Answer:
[tex]y-7=-\frac{\displaystyle 4}{\displaystyle 9}(x+4)[/tex]
OR
[tex]y-3=-\frac{\displaystyle 4}{\displaystyle 9}(x-5)[/tex]
Step-by-step explanation:
Hi there!
Point-slope form: [tex]y-y_1=m(x-x_1)[/tex] where [tex]m[/tex] is the slope and [tex](x_1,y_1)[/tex] is a point that falls on the line
1) Determine the slope (m)
[tex]m=\frac{\displaystyle y_2-y_1}{\displaystyle x_2-x_1}[/tex] where two given points are [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex]
Plug in the given points (-4, 7) and (5, 3):
[tex]m=\frac{\displaystyle 3-7}{\displaystyle 5-(-4)}\\\\m=\frac{\displaystyle 3-7}{\displaystyle 5+4}\\\\m=\frac{\displaystyle -4}{\displaystyle 9}[/tex]
Therefore, the slope of the line is [tex]-\frac{\displaystyle 4}{\displaystyle 9}[/tex]. Plug this into [tex]y-y_1=m(x-x_1)[/tex] as [tex]m[/tex]:
[tex]y-y_1=-\frac{\displaystyle 4}{\displaystyle 9}(x-x_1)[/tex]
2) Plug a point into [tex]y-y_1=-\frac{\displaystyle 4}{\displaystyle 9}(x-x_1)[/tex]
[tex]y-y_1=-\frac{\displaystyle 4}{\displaystyle 9}(x-x_1)[/tex]
Because we're given two points, there are two ways we can write this equation:
[tex]y-y_1=-\frac{\displaystyle 4}{\displaystyle 9}(x-x_1)\\\\y-7=-\frac{\displaystyle 4}{\displaystyle 9}(x-(-4))\\\\y-7=-\frac{\displaystyle 4}{\displaystyle 9}(x+4)[/tex]
OR
[tex]y-3=-\frac{\displaystyle 4}{\displaystyle 9}(x-5)[/tex]
I hope this helps!
Write 6/7 as a decimal rounded to the nearest hundredth
Answer:
0.01
Step-by-step explanation:
6/7% = 6÷7÷100 = 0.0085714286 round to the nearest hundredth = 0.01
What is the value of the capacitance of a capacitor that stores 40
μ
C on each plate, when a potential difference of 10 V is applied to it?
We know
[tex]\boxed{\sf Q=CV}[/tex]
[tex]\\ \large\sf\longmapsto C=\dfrac{Q}{V}[/tex]
[tex]\\ \large\sf\longmapsto C=\dfrac{40}{10}[/tex]
[tex]\\ \large\sf\longmapsto C=4\mu F[/tex]
Solve For X: 12 * X+3=51
Answer:
x=4
Step-by-step explanation:
12 * X+3=51
Subtract 3 from each side
12x +3-3 = 51-3
12x = 48
Divide by 12
12x/12 = 48/12
x = 4
PLZ ANSWER QUESTION IN PICTURE
Answer:
X-int = -5 and y-int = 6
Step-by-step explanation:
1.2x+6 = 0
1.2x= -6
X = -6/1.2
X = -5
a) __m=10km 25m =___km
b) __m=__km__m=1.5 km
Example :
a) 7250m= 7km 250m = 7.250km
Please help me
Answer:
a) 10,025 m = 10km 25m = 10.025 km
b) 1,500 m = 1 km 500 m = 1.5 km
Answer:
a) 10025m = 10km 25m = 10.025km
b) 1500m = 1km 500m = 1.5km
Step-by-step explanation:
Concept:
Here, we need to know the idea of unit conversion.
Unit conversion is the conversion between different units of measurement for the same quantity.
1 km = 1000 m
Solve:
a)
10km 25m = 10×1000 + 25 = 10025 m10km 25m = 10 + 25/1000 = 10.025 kmb)
1.5km = 1 + 0.5 × 1000 = 1km 500m1.5km = 1.5 × 1000 = 1500mHope this helps!! :)
Please let me know if you have any questions
g(x) = f(x+1) using f(x)= x to the power of 2
Answer:
g(x) = x² + 2x + 1
General Formulas and Concepts:
Algebra I
Terms/Coefficients
ExpandingFunctions
Function NotationStep-by-step explanation:
Step 1: Define
Identify
g(x) = f(x + 1)
f(x) = x²
Step 2: Find
Substitute in x [Function f(x)]: f(x + 1) = (x + 1)²Expand: f(x + 1) = x² + 2x + 1Redefine: g(x) = x² + 2x + 1According to Fidelity Investment Vision Magazine, the average weekly allowance of children varies directly as their grade level. In a recent year, the average allowance of a 9th-grade student was 9.66 dollars per week. What was the average weekly allowance of a 5 th-grade student?
The average weekly allowance of a 5th grade student as calculated using direct variation with the information provided by Fidelity Investment Vision Magazine is 5.367 dollars per week.
The question given is a direct variation problem:
Let:
• Average weekly allowance = [tex]a[/tex]
• Grade level = [tex]g[/tex]
If Average weekly allowance varies directly as grade level , then , then the direct variation between the variables can be expressed as :
[tex]a = k * g[/tex]
Where , [tex]k[/tex] = constant of proportionality
We can obtain the value of k from the given values of a and g
[tex]9.66 = k * 9\\9.66 = 9k\\k = 9.66/9[/tex]
Our equation becomes:
[tex]a = (9.66/9) * g[/tex]
[tex]a = (9.66/9) * 5\\a = 5.367[/tex] (rounded to 3 decimal places)
Hence, using proportional relationship, the average weekly allowance for a 5th grade student is [tex]5.367[/tex] per week
Learn more about direct variation here:
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A rectangular floor is 20 feet long and 16 feet broad. if it is to be paved with squared marbles of same size,find the greatest length of each squared marbles.
Answer:
4 ft
Step-by-step explanation:
I guess, the meaning is the largest marbles, so that we can pave the whole floor without cutting any marbles and leaving empty spots.
so, 20×16 ft²
we can have marbles 1/2 ft long. and it all fits well : 40×32 marbles.
we can have them 1 ft long, and it all fits well : 20×16 marbles.
we can have them 2ft long, and it still fits well : 10×8 marbles.
and so on.
so, actually, we are looking for the greatest common divisor (GCD) of 20 and 16. and that gives us the maximum length of a single marble to fulfill the requirement.
let's go for the prime factors starting with 2
20/2 = 10
10/2 = 5
5/3 fits not work
5/5 = 1 done
so, 20 = 2²×3⁰×5¹
16/2 = 8
8/2 = 4
4/2 = 2
2/2 = 1 done
16 = 2⁴
so, for the GCD I can only use powers of 2 (the only prime factors both numbers have in common).
and we have to use the smaller power of 2, which is 2, so, the GCD is 2² = 4
=>
the maximum length of the squared marbles is 4 ft.
that would pave the floor with 5×4 marbles completely.
If p is true and ~ q is false, then p ~ q is _____ false.
a. sometimes
b. always
c. never
PLEASE HELP!!!
Find the equation of the line with an x intercept of 4 and a y intercept of -1.5
Answer:
y = 4x - 1.5
Step-by-step explanation:
The slope intercept form of a line is
y = mx+b where m is the slope and b is the y intercept
y = 4x - 1.5
An F test for the two coefficients of promotional expenditures and district potential is performed. The hypotheses are H0: 1 = 4 = 0 versus Ha: at least one of the j is not 0. The F statistic for this test is 1.482 with 2 and 21 degrees of freedom. What can we say about the P-value for this test?
Answer:
Pvalue > 0.10
Step-by-step explanation:
Given the hypothesis :
H0 : β1 = β4 = 0
H1 : Atleast one of βj is not 0
F statistic = 1.482 ;
Degree of freedom = 2 and 21 ;
DFnumerator = 2
DFdenominator = 21
Using the Pvalue calculator from Fstatistic ;
Pvalue(1.482, 2, 21) = 0.24999 = 0.25
Hence, Pvalue for the test is 0.25
Pvalue > 0.10
Select the expression that has a value of 13.
9 + 3 x (2 ÷ 3) + 6
(9 + 3) x 2 ÷ 3 + 6
9 − (3 x 2) ÷ 3 + 6
(9 + 3 x 2) ÷ 3 + 6
Answer:
9 − (3 x 2) ÷ 3 + 6 is the answer
I need help with that, if you can, plz. I ty it I think is a not sure
Answer:
-5≤x <1
Step-by-step explanation:
sqrt( x+5) / sqrt(1-x)
The numerator must be greater than zero since it is a square root
sqrt(x+5) ≥0
Square each side
x+5≥0
x≥-5
The denominator must be greater than zero (the denominator cannot be zero)
sqrt(1-x)> 0
Square each side
1-x > 0
1>x
Putting these together
-5≤x <1
The starting line up for a basketball team is to consist of two forwards and three guards. Two brothers are on the team. Matthew is a forward and Tony a guard. There are four forwards and six guards from which to choose the line up. If the starting players are chosen at random, what is the probability that the two brothers will end up in the starting line up
Answer:
0.25 = 25% probability that the two brothers will end up in the starting line up
Step-by-step explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
The order in which the players are chosen is not important, which means that the combinations formula is used to solve this question.
Combinations formula:
[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
Desired outcomes:
Matthew plus another forward from a set of 3.
Tony plus another two guards from a set of 5.
So
[tex]D = C_{3,1}C_{5,2} = \frac{3!}{1!2!} \times \frac{5!}{2!3!} = 3*10 = 30[/tex]
Total outcomes:
Two forwards from a set of 4.
Three guards from a set of 6.
So
[tex]T = C_{4,2}C_{6,3} = \frac{4!}{2!2!} \times \frac{6!}{3!3!} = 6*20 = 120[/tex]
What is the probability that the two brothers will end up in the starting line up?
[tex]p = \frac{D}{T} = \frac{30}{120} = 0.25[/tex]
0.25 = 25% probability that the two brothers will end up in the starting line up
The manager of a juice bottling factory is considering installing a new juice bottling machine which she hopes will reduce the amount of variation in the volumes of juice dispensed into 8-fluid-ounce bottles. Random samples of 10 bottles filled by the old machine and 9 bottles filled by the new machine yielded the following volumes of juice (in fluid ounces).
Old machine: 8.2, 8.0, 7.9, 7.9, 8.5, 7.9, 8.1,8.1, 8.2, 7.9
New machine: 8.0, 8.1, 8.0, 8.1, 7.9, 8.0, 7.9, 8.0, 8.1
Required:
Use a 0.05 significance level to test the claim that the volumes of juice filled by the old machine vary more than the volumes of juice filled by the new machine
Answer:
Reject H0 and conclude that volume filled by old machine varies more than volume filled by new machine
Step-by-step explanation:
Given the data:
Old machine: 8.2, 8.0, 7.9, 7.9, 8.5, 7.9, 8.1,8.1, 8.2, 7.9
New machine: 8.0, 8.1, 8.0, 8.1, 7.9, 8.0, 7.9, 8.0, 8.1
To test if volume filled by old machine varies more than volume filled by new machine :
Hypothesis :
H0 : s1² = s2²
H1 : s1² > s2²
Using calculator :
Sample size, n and variance of each machine is :
Old machine :
s1² = 0.37889
n = 10
New machine :
s2² = 0.006111
n = 9
Using the Ftest :
Ftest statistic = larger sample variance / smaller sample variance
Ftest statistic = 0.37889 / 0.006111
Ftest statistic = 62.001
Decision region :
Reject H0 ; If Test statistic > Critical value
The FCritical value at 0.05
DFnumerator = 10 - 1 = 9
DFdenominator = 9 - 1 = 8
Fcritical(0.05, 9, 8) = 3.388
Since 62 > 3.388 ; Reject H0 and conclude that volume filled by old machine varies more than volume filled by new machine
Which expression is equivalent to the given expression?
Answer:
Option C, a³b
Step-by-step explanation:
(ab²)³/b⁵
= a³b⁶/b⁵
= a³b
Answered by GAUTHMATH
Find the missing numerator: 3 1/3 = x/6
[tex]\sf\huge\underline\color{pink}{༄Answer:}[/tex]
[tex]\tt3 \frac{1}{3} = \frac{x}{6} \\ = \tt \frac{10}{3} = \frac{x}{6} \\ = \tt \frac{x}{6} = \frac{10}{3} \\ = \tt6 \frac{x}{6} = 6( \frac{10}{3} ) \\ = \tt\large\boxed{\tt{\color{pink}{x = 20}}}[/tex]
[tex]\color{pink}{==========================}[/tex]
#CarryOnLearning
I need answering ASAP please
Answer:
The choose (D) 1/3
I hope I helped you^_^
In the given figure L1and L2 are two parallel sides . if the area of the rectangle PQRS is 60cm^2 then what is the area of the parallelogram PQRS.
Answer:
Step-by-step explanation:
Believe it or not, the two areas are the same.
The base of the rectangle is PQ
The height of the rectangle is PS
Now look at the parallelogram.
The base is PQ
The height is PS
The area has to be the same in both cases. There is no other way to interpret what is happening.
The scores on an entrance exam to a university are known to have an approximately normal distribution with mean 65% and standard deviation 7.1%. Using the normalcdf function on your graphing calculator, what percentage of students would score 70 or better on this entrance exam?
A. 28.4%
B. 18.9%
C. 24.1%
D. 22.3%
Answer:
The correct answer is - C. 24.1%
Step-by-step explanation:
Given:
mean μ = 65%
standard deviation δ = 7.1 %
solution:
Prob( X>70) = 1 - Prob(x<70)
= P (x-μ/δ ≥ 70 -65/7.1)
= 1 - Prob( (70-65)/7.1)
= 1 - Prob ( z < 0.7042553)
= 0.24065
the percentage of students scoring 70 or more in the exam
= 24.065*100
= 24.1%
can anybody help with this ?
Answer:(
fx).(gx)=D. -40x^3+25x^2+45
Step-by-step explanation:
Frances bought a new dress that was discounted by 24%. she used the following expressions to find the price of the dress after the discount was applied
Answer:
[tex]0.76d[/tex]
Step-by-step explanation:
Given
[tex]Formula = d - (0.24)d[/tex]
Required
Equivalent expression
We have:
[tex]Formula = d - (0.24)d[/tex]
Open bracket
[tex]Formula = d - 0.24d[/tex]
[tex]Formula = 0.76d[/tex]
Can someone help me find the answer?
Answer: B. This function has no intercept. I think B is the correct answer.
Find the value of x.
Answer:
x=3
Step-by-step explanation:
Find the radius and use Pythagoras on the right side
If you were to place $2,500 in a savings account that pays 3% interest
compounded continuously, how much money will you have after 5 years?
Assume you make no other deposits or withdrawals.
Answer:
$2904.59
Step by Step Explanation:
